This application claims the priority of Japanese Patent Application No. 5-281643 filed on Oct. 15, 1993, which is incorporated herein for reference.
1. Field of the Invention
The present invention relates to a shielding structure of an electronic endoscope apparatus provided with a charge coupled device at the end portion thereof to which an electric cautery can be introduced.
2. Description of the Related Art
An electronic endoscope apparatus is provided with a CCD (Charge Coupled Device) at the end portion of an electronic endoscope as a scope. The interior of the body is picked up by the CCD and the image is displayed on a monitor. An electric cautery or the like is introduced into the human body being observed through a medical instrument insertion channel provided in the electronic endoscope so as to resect or the like the deceased part by the electric cautery while observing the image on the monitor.
Since high-frequency noise is produced when the electric cautery is used, an electric shield is formed around the outer periphery of a signal transmission cable which is connected to the CCD so as to prevent the noise from mixing with a video signal or the like.
The conventional shielding structure, however, cannot be said to have a sufficient measure to counter noise, and when the electric cautery is used, noise often mixes with a video signal, which disturbs the image displayed on the monitor screen.